Lightning strikes produce free neutrons, and we’re not sure how

Low energy neutrons not due to cosmic rays or any other previously known source.

For the last 30 years there has been a very small controversy rumbling in the hallowed halls of physics. Way back in 1985, scientists from the then-USSR noted that whenever a thunder storm passed over their neutron detector, they observed an increased flux of neutrons. Unfortunately, they didn't have much in the way of monitoring equipment to really nail down much beyond the initial observation.

Since then, scientists have put forward a couple of potential explanations for the observed flux. One was that the high fields generated during lightning strikes was modifying the trajectories of muons from cosmic ray showers. In short: these are cosmic rays, and this is not interesting. The second was that the gamma rays emitted during the lightning strike generated neutrons, a photonuclear event. But new measurements show that neither of these explanations can explain the data.

The (now) Russian scientists have designed an entirely new experiment that significantly improves their previous results. They installed three neutron detectors that were sensitive to low energy neutrons: one above ground, one partially shielded in a building, and a third underground with heavier shielding. Sitting next to the underground detector was a more traditional neutron detector that is sensitive to high energy neutrons. Finally, the electrical activity of incoming storms was monitored using a variety of instruments, allowing for better correlation between the neutron measurements and the electrical activity of any passing storms.

Why the variety of neutron detectors? Essentially, the researchers need to get rid of the background noise from cosmic rays. The cosmic rays generate muons that collide with something in or very near the detector, resulting in neutrons that have the high energy of the muon being registered. Neutrons from lightning, on the other hand, can only have the energy given up by a fission event, which is then lost in collisions with molecules in the air as they travel to the detector.

The data obtained by the researchers show clear spikes in the low-energy neutron detectors at the same time as the electrical discharges from a storm. Unfortunately, the time resolution of the neutron detectors is only 1 minute, so it is impossible to extract any detailed information about the neutron flux. The use of the three shielded detectors, however, shows the expected decay behavior, indicating that the neutrons are not generated within the detectors themselves.

The high-energy neutron detector also showed some activity during the storm, but this is because the detector still has some sensitivity for low-energy neutrons. Once this was taken into account, the four detectors all agreed. In short, cosmic rays are not the source for the neutron flux observed during lightning strikes.

The new detectors also allowed the researchers to calculate the neutron flux from the storm activity. In the previous experiments, it had been assumed that each detection event corresponded to a single neutron. In a surprising turn up, the new data show that up to 5000 neutrons per cubic meter are produced every second by lightning strikes.

This is very high, and not very compatible with the alternate explanation, neutron production by high energy photons (gamma rays). To generate the number of neutrons the researchers observe would take about 10 million gamma ray photons m-3s-1. Unfortunately, lightning strikes only generate a tiny fraction of that.

At the moment, this research is not of Earth-shattering importance. But it does point to things going on thunderstorms that we just don't know about yet. And that is quite exciting. It is also important to realize that this isn't going to revolutionize our understanding of nuclear physics, so these observations aren't going to lead to new reactor designs or free energy. Still, we will learn more about thunderstorms, which is pretty cool.

Not to nitpick, love the site and all, but is there any way to hide that "netvideo "queen" gets jailtime and owes Hollywood" article out of the "read also:" section for EVERY article? It's not a flattering picture and it's not even relevant.

Fusion is an interesting possibility. Lightning also generates trillions of positrons, which annihilate to release gamma rays. If the positrons are from protium fusion, and the neutrons are from heavy fusion, do the numbers work out right?

Not to nitpick, love the site and all, but is there any way to hide that "netvideo "queen" gets jailtime and owes Hollywood" article out of the "read also:" section for EVERY article? It's not a flattering picture and it's not even relevant.

I've been seeing the "How one man tracked down anonymous" article thumbnail for months. It does get annoying. I figured the purpose of those thumbnails was to advertise new articles, not beat dead horses into a hole in the ground... all the way to china.

It's probably based on number of comments, which would make sense considering anything anon-related pulls commenters out of the woodwork, and probably generates more new and troll accounts than any other topic as well.

Not to nitpick, love the site and all, but is there any way to hide that "netvideo "queen" gets jailtime and owes Hollywood" article out of the "read also:" section for EVERY article? It's not a flattering picture and it's not even relevant.

I've been seeing the "How one man tracked down anonymous" article thumbnail for months. It does get annoying. I figured the purpose of those thumbnails was to advertise new articles, not beat dead horses into a hole in the ground... all the way to china.

It's probably based on number of comments, which would make sense considering anything anon-related pulls commenters out of the woodwork, and probably generates more new and troll accounts than any other topic as well.

It's a weakness in that article recommendation system. It's just not that great for regular readers. We're exploring alternate methodologies for that reason (amongst others) as part of the Ars redesign we're in the midst of.

It's an easy bet that the phenomenon here is related to the stray neutrons noted twenty years back around "cold fusion" experiments... though that doesn't bring a whole lot of comfort.

While more careful experimentation and measurement knocked off (almost all) claims of excess heat, and some neutron production reports vanished with better instrumentation, there have been claims of stray neutrons right up through SPAWAR's 2009 work. But little of that work holds agreement on the cause of the spare bits of cursed neutrality. Jones' moun-catalyzed fusion work is probably the most clearly related.

It should be noted that this kind of neutron detection, in environments where there are sudden and severe changes in temperature and magnetic fields, has fooled a lot of researchers in a lot of places into seeing what isn't there.

Now to wait for SyFy to work up a lame disaster movie over the effects of global warming, increased thunderstorms and how they work building to massive super-thunderstorm that will unleash a photonuclear explosion which obliterates [random city of choice(but probably in Alaska so they can film it in Canada on the cheap{cos it can't achieve the proper level of camp otherwise<the only way it will be worth watching is with large doses of camp>})].

I think what we have here is 'how do lightning strikes affect devices labelled as neutron detectors', and since I'm not going to buy the article .....

Cheers, Mike.

Clearly the point is that lightning generates neutrons.

Not quite. You have device(s) which are designed and built to detect neutrons - and no doubt could be tested in the presence of known source of same - responding more when lightning strikes are around. This is the mental approach to take when things don't appear clear ie. check assumptions.

Lightning must act as an interesting little particle accelerator. First, there's electrons jumping around at pretty high energies, slamming into other particles in ways they wouldn't if the electrons were traveling as a current through a conductive medium. Then you've got air being compressed at pretty high pressures/temperatures (but small areas) as molecules are forced out of the discharge channel at high speeds. Somewhere in there, it wouldn't be surprising to see some interesting high-energy physics at play. IIRC, they also get measurements of positrons out of lightning strikes.

This would be very different from cold fusion. Lightning is definitely not a cold phenomenon.

BTW, the characterization that 5,000 neutrons created per square meter per second is "very high" is only relative to current theories of what is happening in lightning. That's really not a lot of neutrons. That kind of measurement allows for a relatively rare interaction to be happening. Consider that we're dealing with something like 10^25 molecules per cubic meter (depending on altitude) and lightning strikes last a fraction of a second. So if there is an interaction that results in a neutron being ejected, but it only happens to 1 in 10^22 molecules during a lightning strike, that would be enough to create the given neutron flux.

I think what we have here is 'how do lightning strikes affect devices labelled as neutron detectors', and since I'm not going to buy the article .....

Cheers, Mike.

Clearly the point is that lightning generates neutrons.

Not quite. You have device(s) which are designed and built to detect neutrons - and no doubt could be tested in the presence of known source of same - responding more when lightning strikes are around. This is the mental approach to take when things don't appear clear ie. check assumptions.

Cheers, Mike.

Yours is only one path to explore. Definitely one that should be explored, but not the only one worth walking down. Considering it's already been shown that lightning produces gamma rays and positrons, it shouldn't really be considered crazy that it might produce neutrons.

Mike, they did do a parallel control test with 'dummy' neutron detectors of exactly the same construction, only with a decreased ionizing voltage so that the neutrons wouldn't be detected but all other artifacts would be. These did not register neutron counts so the neutron generation is real.

Mike, they did do a parallel control test with 'dummy' neutron detectors of exactly the same construction, only with a decreased ionizing voltage so that the neutrons wouldn't be detected but all other artifacts would be. These did not register neutron counts so the neutron generation is real.

Excellent that they've covered that. Hence my comment about not having access to the article. Where/how did you get it ? Or do you have a subscription ??

"it shouldn't really be considered crazy that it might produce neutrons. " Good. Who said it was crazy ?

Abstract: Under special circumstances, electromagnetic and weak interactions can induce low-energy nuclear reactions to occur with observable rates for a variety of processes. A common element in all these applications is that the electromagnetic energy stored in many relatively slow-moving electrons can -- under appropriate circumstances -- be collectively transferred into fewer, much faster electrons with energies sufficient for the latter to combine with protons (or deuterons, if present) to produce neutrons via weak interactions. The produced neutrons can then initiate low-energy nuclear reactions through further nuclear transmutations. The aim of this paper is to extend and enlarge upon various examples analysed previously, present order of magnitude estimates for each and to illuminate a common unifying theme amongst all of them.

Abstract: Nuclear transmutations and fast neutrons have been observed to emerge from large electrical current pulses passing through wire filaments which are induced to explode. The nuclear reactions may be explained as inverse beta transitions of energetic electrons absorbed either directly by single protons in Hydrogen or by protons embedded in other more massive nuclei. The critical energy transformations to the electrons from the electromagnetic field and from the electrons to the nuclei are best understood in terms of coherent collective motions of the many flowing electrons within a wire filament. Energy transformation mechanisms have thus been found which settle a theoretical paradox in low energy nuclear reactions which has remained unresolved for over eight decades. It is presently clear that nuclear transmutations can occur under a much wider range of physical conditions than was heretofore thought possible.

Yeah this is an interesting developing field, for more info look at lenr-canr.org in the news section for links to some more info (more-and-less legit, some of it) especially interesting are recent presentation talks by leaders in the field doing real science, trying to nail down the requirements for a sustainable reaction.http://lenr-canr.org/wordpress/?p=173

Fusion is an interesting possibility. Lightning also generates trillions of positrons, which annihilate to release gamma rays. If the positrons are from protium fusion, and the neutrons are from heavy fusion, do the numbers work out right?

You could do fusion in your garage. Get a large glass ball, put two electrodes in it, pump some hydrogen in, apply high vacuum pump, apply high voltage. If conditions are right, the characteristic signature of hydrogen fusion is detected. Google "Farnsworth fusor".

Anything you can do in your garage, lightning can do bigger and better.

Actually, there is theoretical explanation for the observed low energy neutron fluxes during such lightning discharges; we published it in two papers as follows:....

Lewis Larsen, President and CEO, Lattice Energy LLC, Chicago, IL USA

Well that's cool stuff. So one has what would otherwise be considered low order reactions - inverse beta transitions - occurring for some short period of time. I suppose in practice the energetics need to get up towards reasonable odds of production to significant measurement level.

Cheers, Mike.

( edit ) I never knew this Wendt back to Rutherford's day either. Thanks for that :-)

Who needs a garage to make a fusor? I did it in my bedroom, and another downstairs in the "living room", not a very big deal, actually. Of course, to get significant fusion at a mere 50kv or so, I have to use deuterium for the fuel. I suppose there's some in the air normally, not a lot but probably enough.

I can't make sense of the 5k neuts/sq anything - is that over the entire surface area of the planet, the cross section of a lightning bolt, what?

My fusor makes around 10 million neutrons/second (20 million fusion events - half the reactions make T and a proton instead) with about 500 watts input....I hope the LENR guys come even close to that - with absolute proof of the reaction rate, something they lack 100% - then and only then will I listen to their boasts that require somehow whole new theories of things - for which we observe no other evidence, and which conflict with things we do indeed observe. Nice try - probably works on the less educated, but no cigar from me.

So lightning could be one heck of a lot less efficient at this and still make quite a few.

I see that someone has already mentioned that inverse beta decay is much more likely. I just wanted to add that the presence of photonuclear production of neutrons would also include a crap-ton more proton-antiproton pairs produced. Both because of the higher electromagnetic cross section (2x [electric monopoles + magnetic dipoles ] versus 2x magnetic dipoles) and because the required energy is lower by a few MeV. Not to mention the fact that you'd expect an even more massive amount of pions, kaons, and eta mesons.

Interesting and possibly important. This seems to relate to a Focus Fusion.

In any event the article highlights in my mind just how hobbled current nuclear research is. If you don't have a big research project for the government to funnel money into you end up nibbling on bones. We really need to reboot the whole way we goes about research energy systems.

Not to nitpick, love the site and all, but is there any way to hide that "netvideo "queen" gets jailtime and owes Hollywood" article out of the "read also:" section for EVERY article? It's not a flattering picture and it's not even relevant.

I've been seeing the "How one man tracked down anonymous" article thumbnail for months. It does get annoying. I figured the purpose of those thumbnails was to advertise new articles, not beat dead horses into a hole in the ground... all the way to china.

It's probably based on number of comments, which would make sense considering anything anon-related pulls commenters out of the woodwork, and probably generates more new and troll accounts than any other topic as well.

It's a weakness in that article recommendation system. It's just not that great for regular readers. We're exploring alternate methodologies for that reason (amongst others) as part of the Ars redesign we're in the midst of.

OT but I have no idea what these users are talking about. Related article thumbnails? Is this only for some?

Chris Lee / Chris writes for Ars Technica's science section. A physicist by day and science writer by night, he specializes in quantum physics and optics. He lives and works in Eindhoven, the Netherlands.